An Essential Guide To The Truths And Myths Of Chemical Weapons

If you were to ask the average person on the street to tell you about chemical weapons, odds are you’ll hear far more in the way of legend, born out of popular culture, than you will anything resembling fact. For most people, the only information they have on chemical weapons comes from movies like The Rock, episodes of 24, or trashy spy thrillers. Worse still, because that level of background knowledge is so low, even those people who can speak with even a basic level of understanding can often be taken as credible, even as they rattle off incredibly misleading information.

I should know this. Before I started really working in the weapons of mass destruction (WMD) field, I wasn’t much better. When I first joined the U.S. Army as an artillery officer, my sum total of chemical defense training was a short period of instruction as a cadet at Fort Lewis. That very limited instruction reinforced the fact that chemical protective suits are awful to wear more than conveying any real functional knowledge about chemical agents and their effects. 

Since moving into the WMD field, I’ve had the fortune to receive a great deal of education on chemical weapons at Lawrence Livermore National Labs, Aberdeen Proving Ground’s Edgewood Area, and a multitude of training courses across the country. I also had the honor of being selected as a National Defense University Countering Weapons of Mass Destruction Graduate Fellow, where I was able to spend two years studying the ins and outs of WMDs at a technical and policy level. Because of this, I’ve been able to work with some of the most brilliant men and women across academia, government, and the military. 


What I hope to debunk here are some of the persistent myths that arise whenever chemical weapons are mentioned in our national discourse. I also must note that I am currently an Army Reservist. As such, it is important to make clear that my views are my own and do not reflect those of the United States Army, the Department of Defense, or the United States Government.

Chemical Weapons Basics

If we’re going to myth-bust about chemical weapons, it might prove helpful to understand some the nuts and bolts that make up the topic. So, to start, understand that chemical agents can be categorized in two ways. The first is by their persistence and the second is by their mechanism of action.

Persistence, as the name implies, is a measure as to how long they’ll remain in the environment. Typically agents are categorized as “persistent” and “nonpersistent,” but it’s important to realize that there’s not a hard line that separates the two categories. It’s more of a spectrum. The longer an agent remains in the environment, the more persistent it is. The quicker an agent disperses, the less persistent it is.

Chemical weapons can also be categorized by their effects on the human body. There are four major types: pulmonary agents, blood agents, vesicants, and nerve agents.

1.) Pulmonary Agents: These were the first chemical weapons to be used on the battlefield. Sometimes also called “choking agents,” these weapons either kill or incapacitate by destroying the lining of the lungs and thus causing them to fill with fluid, preventing the lungs from being able to absorb oxygen. Pulmonary agents include chlorine, phosgene, and chloropicrin. Pulmonary agents are almost all non-persistent, clearing very quickly after release. 

2.) Blood Agents: These agents kill by preventing the blood from being able to absorb oxygen. Think back to basic anatomy. Blood is circulated through the lungs, where it releases carbon dioxide for the body to exhale and collects oxygen to then distribute around the body. While choking agents prevent that oxygen from reaching the blood by destroying the lung lining, blood agents, in turn, affect the red blood cells, preventing them from being able to absorb oxygen. The most common (and well known) agent is hydrogen cyanide. Blood agents are also extremely non-persistent. When this lack of persistence is combined with the relatively high concentrations needed to create casualties, it’s easy to see why blood agents never saw really wide use on the battlefield.

A pyrotechnician of the Society for The Disposal of Chemical Agents and Military Waste (GEKA) prepares a munition for an X-ray examination at a facility in Germany in 2013., AP

3.) Vesicants: These are otherwise known as “blister agents,” and cause severe chemical burns on any exposed skin. The most common vesicant is Sulfur Mustard, otherwise known in popular culture as “Mustard Gas” (which is a misnomer—Sulfur Mustard is actually a liquid), but other vesicants such as Lewisite also exist. 

It’s worth noting that while vesicants can kill you, the percentage of victims who will die is considerably small, around three percent. Death is typically caused by secondary infections caused by the chemical burns. Further, symptoms of Mustard exposure might not appear for several hours, so victims may have moved past their exposure location, as a group of BBC reporters discovered in during the Iran-Iraq war. Depending on their level of contamination, they might actually contaminate others. This can result in victims with contaminated clothing further contaminating other people and locations. As an example of this, Iranian chemical casualties were reported at the time as contaminating the medical staff at rear-area hospitals.

Unlike pulmonary and blood agents, however, vesicants are persistent, with mustard sometimes taking days to weeks to clear. Consequently, vesicants have been used historically almost like minefields; if you contaminate major routes used for resupply, crossroads, or key equipment, then you can impact their operation. This means reinforcements heading to the front might become casualties as they move along contaminated roads. If you contaminate artillery positions, the crew needs to either take time to decontaminate or will have to work in protective chemical gear, which makes them move slower. This is something the Iraqis did during the Iran-Iraq War, mirroring an Imperial German tactic during the 1918 Michael Offensive during World War I. 

4.) Nerve agents: These are the most deadly chemical weapons currently in existence. They degrade the body’s ability to control its own muscles. To put the process somewhat simplistically, imagine you want to ball your hand into a fist. Your body will use a chemical called Acetylcholine, which is used to tell the muscles to contract. If you want to then relax your hand, the body releases an enzyme known as acetylcholinesterase, which binds to the Acetylcholine and inactivates it, which then allows your muscle to relax. Nerve agents target acetylcholinesterase, binding to it and rendering it unusable. As such, if you were exposed to a sufficient amount of nerve agent, you would find it difficult to relax your fist. But, more critically, your body’s ability to pump air in and out of your lungs is impacted, as is the beating of your heart. This is also why one of the telltale signs of nerve agent exposure is pinpoint pupils regardless of the amount of ambient light; the muscles that control the iris of the eye have been commanded to fully constrict.

There are two broad classes of nerve agent: G-Series and V-Series. The G-Series (“G” stands for “German,” since it was Nazi scientists who invented this class of chemicals) include Tabun, Sarin, Soman, and Cyclosarin. The V-Series (“V” stands for “Venomous”) include most prominently VX. 

G-Series agents tend to be nonpersistent (though that persistence varies, more on that later), and V-Series agents tend to be very persistent. As such, G-Series tends to be used more against military objectives that will have to be captured relatively quickly after an attack (imagine attacking a defended hillside, a trench line, bunker complex), whereas V-Series get used against more operational targets (such as airfields, ports, supply routes, major supply depots). 

A chemical warfare training exercise in Iran seen through a gas mask., AP

Again, like sulfur mustard, none of these agents are a “gas,” but are instead liquids. That said, if you want to annoy your local chemical officer, refer to “nerve gas” in his or her presence. At a minimum, you’ll get them to twitch.

So, these are the broad details you need to know to be able to understand what we’re going to talk about next. Here are a few myths that keep getting repeated, often by people who ought to know better.

Definitions Matter: Not Every Unpleasant Weapon is a Chemical One

Watching the news, you’ll hear plenty of people assert that chemical weapons have been used, be it the use of tear gas in any number of domestic protests in the United States to the use of battlefield obscurants, shells that generate clouds of smoke which prevent the enemy from being able to see, either with the naked eye or with thermal sights. But are these actually chemical weapons?

The short answer? No. The long answer? Nooooo! Here’s why. 

Tear gas is classified as a “riot control agent” under the Chemical Weapons Convention. A riot control agent is defined as “Any chemical not listed in a Schedule, which can produce rapidly in humans sensory irritation or disabling physical effects which disappear within a short time following termination of exposure.” States are prohibited to use these on the battlefield, but are permitted for domestic policing purposes. Unpleasant or no, crowd control is a legitimate government responsibility. But it seems strange that an agent that’s permitted for domestic policing would be prohibited on the battlefield Why is this? 

Turkish police fire off tear gas during demonstrations in Istanbul back in 2013. , AP

Simple. During World War I, riot control agents were used in “mask-breaker attacks” which were intended to improve the effectiveness of chemical weapons. Combatants would mix in riot control agents with lethal chemical agents, the intent being that victims would get a lung-full of a riot control agent, then be forced to remove their masks to cough or vomit. In doing so, the victim would then be exposed to a lethal chemical agent, which they would then inhale. It is possible Saddam Hussein did the same during the Iran-Iraq War. He used riot control agents against the Iranians, but it is not clear if he mixed in lethal chemical agents.

White phosphorus, on the other hand, is not intended to have either a lethal or riot-control effect at all. It is intended primarily to screen friendly troops from enemy observation and is intended to have a secondary incendiary effect (which is actually not prohibited under the Convention on Certain Conventional Weapons). Though the idea of being killed in an incendiary attack is unpleasant, it is distinct from that of a chemical attack. More on this when we get to myth #4.

The ‘Kitchen Sarin’ Myth

The most common description of nerve agents is that they are colorless, odorless, and invisible when in the atmosphere. This is true for Sarin, though other agents in the same family as Sarin will have a tell-tale odor (Tabun smells a little like fruit, and Soman smells like mothballs). But this is only when the chemical agents are both pure and on their own.

Sarin itself might not be produced as a pure agent. Pure nerve agent could theoretically be stored for decades, but the more impurities the shorter the shelf-life. Iraqi, for example, during the Iran-Iraq War produced nerve agents as cheaply as possible, but with a high level of impurity, which meant that nerve agent used at the front had to be rushed from the production facility to the firing line.

These impurities were noticeable. When delivered on the battlefield, they would appear as either a dirty-white cloud or with a yellowish-brown hue. Those impurities didn’t impact the effectiveness of the agent; they allowed the Iraqi Republican Guard to win key battles throughout the Iran-Iraq War, including the recapture of the strategically-vital Majnoon Islands in the al Faw Peninsula.

Another example, albeit from a non-state actor, was the first Sarin attack carried out by the Japanese religious cult Aum Shinrkyo. Prior to their attack on the Tokyo subway system, Aum also attacked the small town of Matsumoto north of Tokyo, in revenge for local leaders suing the cult over a fraudulent land deal. The resulting cloud, due to impurities in the Sarin, resulted in a plume that looked not unlike fog, similar to the Iraqi agent used on the Majnoon Islands. In addition, Aum’s production was of a scale not unlike that of a state actor, with a large and complex manufacturing plant established for producing Sarin. This was perhaps a byproduct of just how unique Aum was, given the large number of specialty engineers that called the cult home.

Photo taken in September 1998 shows the Satyam 7 facility at the AUM Shinrikyo cult’s complex in Kamikuishiki, west of Tokyo. The cult mass produced Sarin nerve gas at the facility. , AP

In short, this argument seems to be built on the assumption that if a state is producing a chemical agent, it must be doing so in that agent’s pure form, and conversely, an impure CW agent must point to a non-state actor. As the Iraqi experience shows, states that are at war and under pressure will often skip the expense of producing pure agent and will manufacture with an “as needed” approach. Depending on the agent, some states aren’t even so picky as to turn their nose up at dumpster diving: the Egyptian chemical weapons program in the 1960s acquired its initial batch of sulfur mustard by cracking open artillery shells abandoned by the British military in Egypt at the end of World War I.

Even the United States fell prey to this. When rushing to produce its M55 Sarin rockets during the late 1950s to counter a perceived Soviet advantage in chemical weapons, the Army recycled Sarin from other munitions, which resulted in the introduction of chemical impurities. Those impurities would eventually result in the rockets becoming leaky and unusable, eventually requiring the rockets to be dumped at sea. The environmental rules back then were far more forgiving. 

In short, there is a wide gap between the battlefield and the lab. Though the idea of a mad genius mixing together chemical weapons on his kitchen stove is frightening, the practical constraints are actually far more significant than most might think. And while governments have to be on the lookout for extremists who might be capable enough to produce chemical agents, there’s a reason why the majority of attacks using chemical weapons have come from state actors.

Rescuers wearing gas masks take part in a countrywide Russian Emergency Situations Ministry’s drills in Petropavlovsk-Kamchtsky, Russia, October 3, 2018., AP

Ironically enough, the impurities associated with chemical agents in Syria are often used as supposed evidence that the agent must have been made by the rebels and not the Syrian regime. Of course, this Analysis of the Syrian Government’s own declarations to the OPCW indicates their production method likely only resulted in an agent that was about 60% pure at best, putting it on par with 1980s Iraqi production quality. If a well-advanced state program struggled to get above 60%, what does that tell you about an extremist group’s chances?

Lack of Proper Protective Equipment Points to a False Flag

A common assertion made when defenders of the Assad regime want to distract attention away from a chemical attack is to argue that the Assad regime is not responsible for attacking with chemical weapons because the first responders are not wearing the kinds of protective gear that U.S. first responders would employ if faced with a similar threat. “If they’re not wearing a full chemical suit and mask, how is it they didn’t die immediately upon arrival?” Simple: persistency.

Remember that nonpersistent agents evaporate quickly and are used when you need to move into an area quickly after a chemical attack. If you use a nonpersistent agent like Sarin, the agent will evaporate away into the environment in as little as a half hour. As an example, during the Iran-Iraq War the Iraqi Army used non-persistent nerve agents in this manner to capture the Majnoon Islands, killing hundreds of Iranian troops. The agent dissipated quickly enough to allow Iraqi troops to rush in and capture the objective. 

It was this rapid dissipation that had attracted the U.S. military to Sarin in the 1950s, with Edgewood Arsenal scientists arguing that the volatility of this particular agent would be such that it would rapidly spread into the surrounding environment (thus affecting the maximum number of targets before they had a chance to put on protective equipment) and then dissipate just as quickly. Soman, a much more dangerous nerve agent, was specifically rejected in part because it evaporated too slowly.

So what does this have to do with this particular myth? If you’re moving into an area that has been attacked by nonpersistent agents like Sarin or Chlorine, you’re only going to need full protective suits if you expect exposure to drops or pools of liquid agent. This is most likely during an attack and immediately after, when the agent is being sprayed by its delivery munition. After that point, so long as you don’t touch any puddles of agent, Sarin is primarily an inhalation hazard. Even then, it takes a much larger amount of agent on the skin to cause lethal effects. 

Up until the 1980s, in fact, U.S. troops were trained to simply cut away any part of their clothes splashed with nerve agent, since protective clothing back then was essentially just normal uniforms that had been waterproofed. Say what you will about how unpleasant modern chemical suits are to wear, it could be a lot worse. 

U.S. Soldiers in their warfighting NBC suits prior to Operation Desert Storm. , DoD

Another example of this is when U.S. Army Chemical Corps soldiers used to perform visual inspections of containers of Sarin stored in the open air with only a gas mask and wearing their normal uniform. Yet another example is this U.S. chemical weapons scientist placing a drop of nerve agent into a rabbit cage. Though he wears gloves and a mask, he is wearing a normal lab coat and much of the skin around his wrist and neck are exposed. Also, observe these chemical troops handling leaking Sarin bombs: though they’re wearing chemical gear to protect against the splash hazard, the backs of their heads are fully exposed.

Also, remember that exposure to chemical agents isn’t a binary thing. The dose matters. Depending on your overall size, age, and health, just being exposed may not be enough to kill or even incapacitate you. If the dose is small enough, you might not even notice. If you’re arriving at the scene of an attack and the chemical agent has faded away to only a small level, you might inhale a dose and not be affected, or inhale such a small dose that you might only feel the effects later. This happened at Khan Sheikhoun, where first responders who had been at the scene of the attack arrived at the hospital and then had to seek treatment themselves. This was also a common occurrence during the Tokyo subway attack.

Assuming you’re a rebel in the middle of Syria and you’re expecting a chemical attack, why wouldn’t you just buy a suit and mask from eBay just to be safe? Simple answer: sustainment. 

You need to remember that most modern chemical protective equipment has a shelf-life. The Joint Service Lightweight Integrated Suit Technology (JSLIST) suits the United States uses are issued in vacuum-sealed bags for a reason. These suits are designed to ensure that the individual user is somewhat comfortable while wearing them. Comfort is, of course, a relative term—there are very few service members who will react with excitement at the prospect of having to don their suits. To accomplish this, the suits are semi-permeable and have an activated charcoal liner. This is designed to allow (some) air to pass through the suit, but for chemical contaminants to be trapped by the liner. The problem is, the longer a suit is exposed to the outside air, the more environmental contaminants the liner will absorb. At a certain point, the charcoal won’t absorb any more agent, which in turn means that those agents will simply soak through and reach a soldier’s skin. 

Airmen don Mission Oriented Protective Posture (MOPP) protective gear at the Alpena Combat Readiness Traning Center, Alpena, Michigan during a chemical warfare training exercise. , USAF

Worse, sufficient localized exposure can overwhelm the charcoal of a given area. There is a reason why you’re not supposed to kneel when wearing a JSLIST suit. If you do, and the ground is wet, the fluid will soak right through to the skin, carrying with it any contaminants that might be in the area. Charcoal might slow down permeation, but it won’t stop it.

A common rejoinder might be asking me what protective steps I would take if I were going into an environment I knew to be contaminated. In a perfect world, I’d want to be in a full Mission Oriented Protective Posture (MOPP) suit. Failing that, I’d want to be in Tony Stark’s Iron Man suit. That said, however, if we’re really playing this game, then I’d say that more ideally I’d rather to be at home safe on my couch, and letting somebody else handle it. No matter what, as we sit at home and watch the Syrian Civil War unfold, we’re not faced with the same dilemma as people on the ground there. For us, we might want a full chemical suit. For them, they likely understand that one won’t be forthcoming and standing around while people slowly die isn’t an option. 

“Why Do We Make Such a Big Deal About Chemical Weapons When Thousands Are Killed by Conventional Weapons?”

Another popular observation surrounding chemical weapons is the assertion that it’s silly to worry about chemical weapons attacks, especially in places like Syria, when conventional weapons cause so many more deaths. While this seems to make some degree of sense on the surface, once you dig a little deeper you will discover that it’s far more complicated.

Chemical agents are a uniquely horrible form of warfare. The PTSD rates for combatants and noncombatants alike forced to fight and survive in a chemical environment are high, and exceed that even of high-intensity conventional warfare, and it is an effect that is passed from the survivors to their children. To deliberately deploy ignorant tropes to either protect the perpetrators or flat out deny that victims even exist is morally reprehensible.

Chemical weapons are actually uniquely suited to targeting civilian populations. Even a semi-modern military can relatively effectively provide defenses to their troops against chemical weapons. You field protective masks and suits, you create vehicles with sealed interiors, and you provide decontamination assets to allow any chemically-exposed troops to clean themselves off. Yet providing the same amount of protection to an entire civilian population is extraordinarily cost prohibitive. 

Knowledge of how to use chemical equipment is also a perishable skill. It’s far harder to ensure that a civilian population knows how to use chemical protective equipment, even if you could afford to provide it to the bulk of the population. Consider that more Israeli civilians died from misusing their own gas masks than they did from Iraq’s Scuds themselves during Desert Storm. Chemical gear isn’t foolproof. It requires training on the part of the user. It’s far easier to factor in training for military formations than it is for a civilian populace.

Israeli citizens periodically train to dawn gas masks at a moments notice. , IDF

Given the scale problem with defenses, consider then a conventional weapon placed next to a chemical one. Generally speaking, you can offer similar protection to a civilian from bomb damage about as much as you can a uniformed combatant. After all, a wall or basement offers the same protection against shell fragmentation to a combatant as it does a civilian. A chemical weapon, however, potentially offers the scenario where a combatant will likely be safely protected by his or her protective mask, while a civilian likely will not.

Of course, the world has been very lucky in that chemical attacks against civilian targets have been relatively restrained. We can, in part, thank the norm against chemical use for this. When chemical weapons use risks international outrage, it incentivizes the user to try to keep the scale as low as possible. This, in turn, helps reduce the death toll. When chemical weapons use becomes normalized, the potential for increased civilian casualties rises dramatically. 

“Why Would Assad Use Chemical Weapons? What Does He Have to Gain?”

This is a topic I’ve written about previously, but it is still almost inevitable that whenever there is a report of a chemical weapon attack in Syria, people will inevitably ask “what does Assad have to gain using chemical weapons?” Often, this question is not raised honestly. That said, it preys on ignorance both about the war in Syria and chemical weapons in particular. Simply put, chemical weapons have been a useful tool to the Syrian regime. 

Given all we’ve talked about up to this point, this shouldn’t be too surprising a proposition. Insurgents and their host populations can’t protect themselves against chemical weapons nearly as well as they can conventional bombs. More to the point, the sheer terror factor of chemical attacks have their own utility. Counterinsurgents seek to defeat their adversaries by separating them from the population. In doing so, insurgents lose their necessary support base and are denied the natural concealment afforded by being able to blend into population centers. The Assad regime has used indiscriminate strikes on civilian population centers, from cluster munitions to barrel bombs, to affect such a population drain.

Hazardous chemicals that are used to produce chemical weapons. , AP

Idlib, the last remaining area outside of Syrian Regime control, actually stands testament to how well this works. The sheer number of refugees that have crowded into Idlib have in turn come from other areas subjected to similar indiscriminate population attacks. Defenders of the regime will often point to the fact that civilians fleeing from these areas were provided with buses to help with their evacuation. But the entire point of these air attacks was to make such transfers seem attractive, so as to drain the final sources of rebel support. Small chemical attacks, then, serve a key purpose despite their comparatively low body counts.

Finally, this myth also shows a real ignorance of the dynamics of the Syrian conflict. For most western political audiences, there have only been a couple of chemical attacks. There was the Ghouta attack in 2013 (which resulted in the Syrian regime cynically joining the CWC while essentially continuing their chemical campaign), the Khan Sheikhoun attack in 2017, and the Douma attack in 2018. Those last two attacks resulted in retaliatory strikes by the United States and its allies. Yet there have actually been at least 50 chemical attacks across Syria since the start of the civil war. Other open source researchers have identified over 250 attacks. Chemical attacks in Syria aren’t the one-off things that conspiracy theorists like to pretend they are.


Despite the Chemical Weapons Convention, it is likely that the world will have to deal with chemical weapons for the foreseeable future. Multiple countries, such as Egypt, Israel, and North Korea, remain outside the Convention. Further, signatories like Syria continue to flaunt their obligations under the convention. In addition, given events in the news, it seems that chemical weapons remain an attractive

option for state actors even at low-levels.

Russian soldier geared up for a chemical warfare combat enviroment., AP

Despite this, the international norm against chemical weapons matters. The stronger that norm is, the harder it is for states to get away with using chemical weapons, which means that they’ll ever eschew them completely or be forced to limit the scale of their use. There are numerous projects, such as CSIS’ Restoring Restraint, which seek to find ways to strengthen these norms further. But in order to do this, the public at large have to understand what chemical weapons are, what they aren’t, and what they can and can’t do. Education, in other words, is crucial. Hopefully, this quick explainer can play some role in that process.

Luke J. O’Brien is an analyst and military historian, a CSIS Project on Nuclear Issues Mid-Career Cadre, and is a contributing editor at War on the Rocks. He is also an officer in the US Army Reserve, and as such his views are his own and not those of the Army, the Department of Defense, or the United States Government. He can be found on Twitter as @luke_j_obrien.

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